THYROID-DISEASE AND BREAST-CANCER

A review of the literature on the relationship between thyroid disorde rs and breast cancer does not provide conclusive evidence for the esta blishment of a causal relationship as breast cancer has been associate d with hypothyroidism, hyperthyroidism and nontoxic goiter. Most repor ts on the association of thyroid enlargement and breast cancer have em anated from areas of endemic iodine deficiency and these reports have relied on neck palpation. The contribution of the present study is in the application of the highly sensitive technique of diagnostic ultras ound to the investigation of subtle changes in thyroid volume and anat omy in patients with breast cancer. The mean thyroid volume of 20.4+/- 1.0 ml in 184 breast cancer patients was significantly greater than th at of 12.9+/-1.2 ml in age-matched controls (p<0.01). Also the number of individual patients with breast cancer having enlarged thyroid glan ds (73/184; 39.7%) was significantly greater than the corresponding nu mber (13/150; 8.6%) in the control group (p<0.001). There was a direct correlation between thyroid enlargement and breast tumour staging. Bo th mean thyroid volume and % of enlarged thyroids were identical in gr oups of patients scanned after (Retrospective Group) and before (Prosp ective Group) various therapies for breast cancer, thus excluding ther apeutic intervention as a cause for thyroid enlargement. The results i ndicate a direct relationship between the two disorders perhaps involv ing a common growth stimulus and emphasise the importance of raising t he consciousness of the coincidence of both disorders.